This invention relates in general to a vehicle wheels and in particular to a light weight cast wheel for commercial highway vehicles and an apparatus for casting such a wheel.
Light weight commercial vehicle wheels formed from an aluminum alloy are becoming increasingly popular. It is known to fabricate such wheels from two pieces. A full face wheel disc is formed by a conventional process, such as casting or forging, from an alloy of a light weight metal, such as aluminum, magnesium or titanium. The wheel disc includes a centrally located wheel mounting flange and an outer annular flange which forms an outboard tire bead seat retaining flange. The centrally located wheel mounting flange has a centrally located pilot hole and a plurality of lug bolt holes spaced circumferentially around the pilot hole. The lug bolt holes receive lug bolts which carry nuts for securing the wheel on an axle of a vehicle. The outer annular flange of the disc is preferably provided with a plurality of wheel openings or windows spaced circumferentially around the pilot hole. The perimeter of the outer flange is formed into an outboard tire bead seat. An outboard tire bead retaining flange extends in an outward radial direction from the outboard end of the tire bead seat.
The wheel disc is attached to the outboard end of a partial wheel rim at the outboard tire bead seat with a continuous air-tight circumferential weld. The partial wheel rim is formed by a conventional process, such as rolling and includes a wheel well which extends in an axial inboard direction from the outboard tire bead seat. The well terminates in an inboard tire bead seat. An inboard tire bead retaining flange extends radially from the inboard end of the inboard tire bead seat. The wheel rim is usually formed from the same alloy as the wheel disc; however, the rim can be formed from a different metal. To reduce cost, the wheel rim can be rolled from steel.
Alternately, a one piece wheel can be formed by a conventional process, such as casting or forging. A one piece wheel eliminates the circumferential weld between the wheel disc and wheel rim and the potential for air leaks therethrough. However, because of the geometry of the molds or dies used, such wheels tend to have thick cross sections at the juncture of the wheel disc outer annular flange and the outboard end of the wheel rim.